xref: /petsc/src/dm/dt/tests/ex6.c (revision 732aec7a18f2199fb53bb9a2f3aef439a834ce31)
1c4762a1bSJed Brown static char help[] = "Tests 1D Gauss-Lobatto-Legendre discretization on [-1, 1].\n\n";
2c4762a1bSJed Brown 
3c4762a1bSJed Brown #include <petscdt.h>
4c4762a1bSJed Brown #include <petscviewer.h>
5c4762a1bSJed Brown 
main(int argc,char ** argv)6d71ae5a4SJacob Faibussowitsch int main(int argc, char **argv)
7d71ae5a4SJacob Faibussowitsch {
8c4762a1bSJed Brown   PetscInt   n = 3, i;
9c4762a1bSJed Brown   PetscReal *la_nodes, *la_weights, *n_nodes, *n_weights;
10c4762a1bSJed Brown 
11327415f7SBarry Smith   PetscFunctionBeginUser;
12*c8025a54SPierre Jolivet   PetscCall(PetscInitialize(&argc, &argv, NULL, help));
139566063dSJacob Faibussowitsch   PetscCall(PetscOptionsGetInt(NULL, NULL, "-n", &n, NULL));
14c4762a1bSJed Brown 
159566063dSJacob Faibussowitsch   PetscCall(PetscMalloc1(n, &la_nodes));
169566063dSJacob Faibussowitsch   PetscCall(PetscMalloc1(n, &la_weights));
179566063dSJacob Faibussowitsch   PetscCall(PetscMalloc1(n, &n_nodes));
189566063dSJacob Faibussowitsch   PetscCall(PetscMalloc1(n, &n_weights));
199566063dSJacob Faibussowitsch   PetscCall(PetscDTGaussLobattoLegendreQuadrature(n, PETSCGAUSSLOBATTOLEGENDRE_VIA_LINEAR_ALGEBRA, la_nodes, la_weights));
20c4762a1bSJed Brown 
219566063dSJacob Faibussowitsch   PetscCall(PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_SELF, "Gauss-Lobatto-Legendre nodes and weights computed via linear algebra: \n"));
229566063dSJacob Faibussowitsch   PetscCall(PetscRealView(n, la_nodes, PETSC_VIEWER_STDOUT_SELF));
239566063dSJacob Faibussowitsch   PetscCall(PetscRealView(n, la_weights, PETSC_VIEWER_STDOUT_SELF));
249566063dSJacob Faibussowitsch   PetscCall(PetscDTGaussLobattoLegendreQuadrature(n, PETSCGAUSSLOBATTOLEGENDRE_VIA_NEWTON, n_nodes, n_weights));
259566063dSJacob Faibussowitsch   PetscCall(PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_SELF, "Gauss-Lobatto-Legendre nodes and weights computed via Newton: \n"));
269566063dSJacob Faibussowitsch   PetscCall(PetscRealView(n, n_nodes, PETSC_VIEWER_STDOUT_SELF));
279566063dSJacob Faibussowitsch   PetscCall(PetscRealView(n, n_weights, PETSC_VIEWER_STDOUT_SELF));
28c4762a1bSJed Brown 
29c4762a1bSJed Brown   for (i = 0; i < n; i++) {
30c4762a1bSJed Brown     la_nodes[i] -= n_nodes[i];
31c4762a1bSJed Brown     la_weights[i] -= n_weights[i];
32c4762a1bSJed Brown   }
339566063dSJacob Faibussowitsch   PetscCall(PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_SELF, "Difference: \n"));
349566063dSJacob Faibussowitsch   PetscCall(PetscRealView(n, la_nodes, PETSC_VIEWER_STDOUT_SELF));
359566063dSJacob Faibussowitsch   PetscCall(PetscRealView(n, la_weights, PETSC_VIEWER_STDOUT_SELF));
36c4762a1bSJed Brown 
379566063dSJacob Faibussowitsch   PetscCall(PetscFree(la_nodes));
389566063dSJacob Faibussowitsch   PetscCall(PetscFree(la_weights));
399566063dSJacob Faibussowitsch   PetscCall(PetscFree(n_nodes));
409566063dSJacob Faibussowitsch   PetscCall(PetscFree(n_weights));
41c4762a1bSJed Brown 
429566063dSJacob Faibussowitsch   PetscCall(PetscFinalize());
43b122ec5aSJacob Faibussowitsch   return 0;
44c4762a1bSJed Brown }
45c4762a1bSJed Brown 
46c4762a1bSJed Brown /*TEST
47c4762a1bSJed Brown 
48c4762a1bSJed Brown    test:
49c4762a1bSJed Brown 
50c4762a1bSJed Brown TEST*/
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